Write to the Secretary of BSS, Mr DA Young, (Dept I), 112 Whitehall Road, North Chingford, London
Patrick Powers ---------- From: sundial-approval To: sundial Subject: Re: declination Date: 14 May 1996 00:22 I am interested in the method described below. Could someone let me know how I might purchase a back copy of BSS bulletin no 92.1 so that I may have access to the article on pages 33 - 35. I am planning to build a large vertical sundial the south facing side of a horse barn at a Girl Scout Camp in upstate New York, USA. Thank you Ed >Reading the question of Rolf Menzl, [EMAIL PROTECTED] about declination of a wall. > >For a plane, on which a dial has to be constructed we need to know the latitude, the declination and the >inclination of that plane. >If we do know these and we place a gnomon with length g perpendicular to the plane we can calculate the x-y >coordinates of the shadowpoint of the tip of the gnomon for a certain date and (sun)time. >This procedure can be used in reverse to determine the declination and inclination of a plane if we know the >latitude, the date and (sun)time and the coordinates of a shadowpoint of the gnomon with length g. > >About this problem I held a lecture when I visited the conference of the British Sundial Society in Cambridge >in 1991. >This lecture with formulas is published in English in the BSS bulletin no 92.1 page 33 - 35. >I myself learned this methode after a publication in the bulletin of De Zonnewijzerkring, (the dutch Sundial >Society) in 1981. >In this bulletin the procedure is published again in 1991 and 1992. (in dutch) > >This procedure gives two solutions for the declination and inclination, when using a single shadowpoint. >By using two shadowpoints the wrong values can be elminated. >This methode is uniform all over the world. > >I have no electronic version of this lecture to send with this message. > >Fer J. de Vries >[EMAIL PROTECTED] >
